In sports there have been certain barriers that, once broken, suddenly get surpassed by a surprising a number of athletes. The 4-minute mile is an obvious example. Initially it was thought to be unbreakable, but as athletes got closer and closer, they realized it would be broken – and suddenly, a good number of athletes did so in close succession. Today CrossFit athletes break that barrier with some regularity. Do you continue to get better? How long have you been training? It's time to test yourself and start knocking holes in some of these walls.